(1) Field of the Invention
The invention relates to networking. More specifically, the invention relates to coordination of networking protocols between two networking devices.
(2) Background
Certain communication protocols have been popularized in existing networking systems. In North America, the predominant protocol is T1 which transmits information at 1.544 megabits per second. T1 typically carries DS1 frames which are composed of 24 bytes plus a framing bit in a 125 microsecond frame. T1 provides twenty-four data channels as a trunk interface. The information is contained in the timing of the signals and not their polarity. A T1 transmission uses a bipolar return to zero alternate mark inversion line coding scheme to keep the DC carrier component from saturating the line.
The other predominant communication protocol is E1, referring to the European framing specification. The protocol is widely used in Europe and Asia. E1 conducts transmission of thirty DS0 data streams at a transmission rate of 2.048 megabits per second. E1 has two subprotocols, balanced and unbalanced, which refers to certain characteristics of the transmission line. Issues arise when a network device executing an E1 protocol is connected to a networking device executing a T1 protocol. Such communication is unlikely to result in any valid data transmission. Some existing systems are designed to have internal switches which permit the user to open the box and manually/mechanically switch from an E1 protocol to a T1 protocol, or vice versa. Then based on the switch position, software loads the appropriate configuration information for the protocol selected. However, this involves opening the box with its attendant inconveniences. Repeated opening of the box may result in damage to sensitive internal components, particularly if exposed to dust or other contaminants. Moreover, user selected configuration assumes knowledge by the user which may not be present.